Burning issues with NEC ND-3100AD

My burner won’t support 16x DVD+R’s. Do I need to update it or what?

You can try to update to NEC 3500 with a conversion tool and then update the firmware . It may be time to buy a new drive . Your drive is more than thee years old. My nec 3500 still work okay but I have a few 16x and 20x drives
heres the link. good luck.
http://liggydee.cdfreaks.com/page/en/NEC-ND-3500A/